Separation of organic compounds at low temperatures.



ED- STATES PATENT. OFFICE;

WALTER E. ND, 0]! WILMINGTON, DELAWARE, ASSIGNOR TO E. I. no PONT nnNEMOUBS POWDER COMPANY, OF WILMINGTON, DELAWARE, A. GORPOBA- TION F NEWJET.

SEPARATION UP ORG G @OMTOUNDS AT LOW TEMPERATURES.

answer.

No llh'ennmg.v

My invention relates particularly to the separation of olefins, thoughit may be used to separate mixtures of other organic comounds. Amongother compounds. to wh ch my invention may be applied arethe ringhydrocarbons or derivatives thereof. 4

The object of my invention is to provide a process for the separation ofolefins and other or anic compounds in an economical manner, at to alsoprovide a process for the production of alcohols and acetic esters.

Mixtures of olefins often contain constituents which will react verydiderentlywith reagents. This is especially true of such olefins aspentylenes and hexylenes, which have been obtained by the treatment ofpentanes and hexanes by chlorination to reduce monochlorhydrocarbons,and w ere these monochlorhydrocarbons have been subjected toacetylation. The acetylation produces as a by-product, a mixture of ole,the several constituents of which behave very difi'erently towardreagents.

@ne of the objects of my invention is to separate such compounds, andparticularly olefins, without having recourse to high temperaturesllnasmuch as the method of separation involves preferably the use ofhydrochloric acid and, in some cases, strong hydrochloric acid,disadvantageous results have occurred in the use of preceding processesby reason of the high temperatures involved and the consequent corrosionof the vessels. using my process, the high temperatures may be entirelyavoided, and there is, consequently, no occasion to use expensivevessels such, for example, as those made of platinum or silver, to avoidcorrosion by the action of the strong hydrochloric acid at the hightemperatures previously used.

My invention is an improvement upon the process described and claimed inmy application for Letters Patent of the United States entitledSeparation of organic com- Epeetfioatlon of Letters Patent.

poplpdsfl and executed on even date here wi While my invention may beapplied to the separation of many did'erent organic compounds, asindicated above, ll Will describe my invention as applied to theseparation of the olefins obtained as above.

The mixture of amylenes and hex lenes is allowed to stand or agitatedwith (t e latter requiring'a shorter length of time) strong hydrochloricacid, that 1s, ordinary concentr'ated-acid of commerce, or relativelydilute hydrochloric acid. it should be noted in this connection that inthis step of the process, acid of practically any concentration can beused, since very dilute hydrochloric acid will react to a certain extentwith the production of chlorhydrocarbons, althou h in a commercialprocess tlxis reaction may e too slow to be of co sidera-ble practicalvalue. The reactio is eflected at ordinary temperatures. The olefins inrt combine with the hydrochloric acid to Worm chlorhydrocarbons of theparaffin series, the hydrocarbon amvlene reacting in the followingmanner:

"OJ-l HCl C TLCl Amyleno Hydrochloric nmy l acid chlorid After theolefins have reacted with the hydrochloric acid to formchlorhydrocarbons of the paraflin series, as already described in theapplication, the oily layer obtained is separated from the spent acidand distilled. The unchanged olefins obtained as a distillate are thensubjected to the action of concentrated hydrochloric acid and calciumchlorid or other dehydrating agent at ordinary temperatures. The olefinsthus treated atented Teb. %4, 1914., application filed Octoter ll, wilt.terial lilo. ltttltt.

.that it is satisfactory for the first step in the process. On the otherhand since this residual acid contains calcium chlorid it is morereactive than ordinary dilute hydrochloric acid, and for this reason itmay be employed in the first stage in the process even when the strengthof the acid as expressed in per cent. of HCl has fallen considerablybelow that of ordinary dilute hydrochloric acid, the strength of whichis also ex ressed in the terms of per cent. of HCl. t may be seen inthis way that if desirable it is unnecessary to discard as useless inthe process any hydrochloric acid and calcium chlorid mixture, as thesame may always be employed, if found desirable, in the first step inthe process as long as it contains any appreciable quantity ofhydrochloric acid. It should also be noted in connection with the secondstage of the process, in which concentrated hydrochloric acid andcalcium chlorid are used, that the acid mixture remaining after such atreatment may be of sufficient strength to be used over again ina'similar. treatment before it becomes weakened to such an extent thatit is valuable only for use in the first step ofthe process.

In regard to the length of time required for the reaction this may varyconsiderably since the degree of conversion into chlor hydrocarbonsobtained in each treatment, depends to a great extent on the duration ofthe treatment. It has been found advantageous however, to continue theagitation of the mixture for from 12 to 24 hours in each case, althoughit may readily be understood that the operation may be carried on for ashorter or longer period as desired.

- In regard to the quantities of reagents employed, obviously the samestatement holds true, as the quantity of reagent employed merely afiectsthe degree of conversion. I have found it advantageous however, to usewith one part of the olefin mixture from two to four parts oftheacid andfrom one to three parts of the calcium chlorid.

With regard to the temperature of distil-' lation it should be notedthat this depends entirel on the olefins employed, but in the case 0 amixture of amylenes and hexylenes the temperatures of distillation wouldrange from about 25 to about 80 C. Obviously the temperature at whichthe distillation is interruptedmerely affects the degree of se arationof the unchanged olefins from t e chlorhydrocarbons and in order toobtain the most satisfactory separation a'maximum be, as indicated,utilized in an temperature of about to C. is the most satisfactory inthis particular case.

The chlorhydrocarbons thus obtained may manner found desirable, but thechlorhy rocarbons obtained by treatment with hydrochloric acid of lowconcentration, are well adapted for the roduction of monohydricalcohols, while t e other chlorhydrocarbons are ada ted for theproductionof acetates, as by t e process of acetylation with acetic acidand sodium .or potassium acetate. These former chlorhydrocarbons, iftreated in the same manner as the chlorhydrocarbons obtained in thelatter stage of the process, would be broken down again into olefins.

The method of obtaining alcohols from certain of the chlorhydrocarbonsis covered by a co-pending patent application of mine, Serial N 0.725,163.

The treatment of these mixed olefins without separation, in order toproduce atcohols and acetates,-would evidently result in poor yields,and would, consequently, be

an expensive operation, while after the olcbeing carried out at a lowtemperature,

avoids the necessity of using expensive apparatus and avoids the need ofsupplyinga great amount of heat for high temperatures.

While I have described my invention above in detail, I wish it to beunderstood that many changes may be made therein without departing fromthe spirit of my invention. Furthermore, it is to be understood thatwherever I have used the term low concentration herein, I mean therebymerely a concentration which is low as compared with the concentrationused in the latter stage of the process. Furthermore, the concentrationused in the latter stage of the process may be obtained by the use ofany dehydratin agent found to be desirable, and that wherever I havemade reference to the use of calcium chlorid, I contemplate the useinstead of any other desired dehydrating agent.

I claim: 7 I

.1. The process which comprises separating isomeric aliphatichydrocarbons by treating them with a solution of a reagent capable ofacting upon only some of the isomers first at a low concentration,separating out the portion acted upon and then treating the unchangedremalning portion with a solution of the reagent at a higherconcentration to act upon other .isomers.

2. The process which comprises separating isomeric aliphatic unsaturatedhydrocarbons by treating them with a solution of a' reagent capable ofacting upon only some nosaeei of the isomers first at a lowconcentration, separating out the portion acted upon and then treatingthe unchanged remainin portion with a solution of the rea ent ata igherconcentration to act u on ot er isomers.

.3. The process whic comprises separating isomeric olefins by treatingthem with a solution of a reagent capable of acting upon only some oithe isomers first at a low concentration, separating out the portionacted upon and then treating the unchanged remaining portion with asolution of the re-. agent at a higher concentration.

4. The recess which comprises separating isomer1c aliphatic hydrocarbonsby treat ing them with hydrochloric acid first at a low concentration,separating out the portion acted upon and then treatin the unchangedremaining portion wit hydrochloric acid at a igher concentration.

5. The process which comprises separating isomeric aliphatic unsaturatedhydrocarbons by treating them with hydrochloric acid first at a lowconcentration, separating out the portion acted upon and then treatingthe unchanged remaining portion with hydrochloric acid at a hi herconcentration.

6. The process whic comprises separating isomeric olefins by treatingthem with hydrochloric acid first at a low concentration, separating outthe portion acted upon and then treating the unchanged remaining portionwith hydrochloric acid at a higher concentration.

7. The process which com rises separating isomeric aliphatic hyrocarbons by treating them with a solution of a reagent capable oilacting upon only some oi the isomers first at a low concentration,separating out by distillation the portion acted upon, and then treatingthe unchanged remaining ortion with a solution of the reagent at ahigher concentration to act upon other isomere.

8. The process which comprises separating isomeric aliphatic unsaturatedhydrocar bons by treating them with a reagent capabio of acting upononly some of the isomers first at a low concentration, separating out bydistillation the portion acted upon, and then treating the unchangedremaining portion with the reagent at a higher concentration to act uponother isomers.

9. The process which comprises separating olefins by treating them witha solution of a rea ent capable of acting upon only some of the isomersfirst at a low concentra-* tion, separating out by distillation theportion acted upon, and then treating the unchanged remainmg portionwith a solution of the reagent at a higher concentration to act uponother isomers.

10. The process which comprises separating isomeric aliphatichydrocarbons by treating them With hydrochloric acid first at a lowconcentration, separating out by distillation the portion acted upon,and then treating the unchanged remaining portion with hydrochloric acidat a higher concentration.

11. The process which comprises separating isomeric aliphaticunsaturated hydrocarbons by treating them with hydrochloric acid firstat a low concentration, separating out b distillation the portion actedupon, and t on treating the unchanged remaining portion with hyrochloric acid at a higher concentration. 12. The process which comrises separatmg isomeric olefins by treating them with hydrochloric acidfirst at a low concentratmn, separating out by distillation the por tionacted upon and then treating the unchan ed remaining portion withhydrochloric acid at a higher concentration.

13. The process which comprises separating isomeric pentylenes andheirylenes by treating them with a solution or" a reagent capable ofactin upon only some of the isomers first at alow concentration, searating out the portion acted upon, an then treating the unchangedremaining portion with a solution of the reagent at a higherconcentration to act upon other isomers.

1d. The process which comprises separating lSOll'lGIlO pentylenes andheuylenes by treating them with hydrochloric acid first at a lowconcentration, separating out the portion acted upon and then treatingthe unchanged remaining portion with hydrochloric acid at a higherconcentration.

15. The process which comprises separating isomeric pent-ylenes andhexylenes by treating them with a solution of a reagent capable of actinupon only some of the isomers first at a low concentration, separatingout by distillation the portion acted upon, and then treating theunchanged remaining portion with a solution of the reagent at a higherconcentration to act upon other isomers.

16. The process which comprises separating isomeric pentylenes andhenylenes by treating them with hydrochloric acid first at a lowconcentration, separating out by distillation the portion acted upon andthen treating the unchanged remaining portion with hydrochloric acid ata higher concentration.

17. The process which comprises separating isomeric aliphatichydrocarbons by treating them with hydrochloric acid first at a lowconcentration, separating out the portion acted upon and then treatingthe unchanged remaming portion with hydrochlorlc acid at a higherconcentration in the presence ct calcium chlorid.

18. The process which comprises separating isomeric aliphaticunsaturated hydrocarbons by treating them with hydrochloric chlorid. I

20. The process which com rises separating isomeric aliphatic hrocarbons by treating them with hydroch oric acid first at [I alowconcentration, separating out by distillation the portion acted upon,and then treating the unchanged remaining portion with hydrochloric acidat a higher concentration in the presence of calcium chlorid.

21. The rocess which comprises separating isomeric aliphatic unsaturatedhydrocarbons by treating them with hydrochloric acid first at a lowconcentration, separating out by distillation the portion acted upon,and then treatin the unchanged remaining portion with hydrochloric acidat a higher concentration in the presence of calcium chlorid.

22. The process which comprises separating isomeric olefins by treatingthem with hydrochloric acid first at a low concentration, separating outby distillation the portion acted upon and then treat-ing the unchangedremalning portion with hydrochloric acid at a higher concentration inthe presence of calcium chlorid.

23. The process which comprises separating isomeric aliphatichydrocarbons by treating them with hydrochloric acid first at a lowconcentration, separating out the portion acted upon, then treating theunchanged remaining portion with hydrochloric acid at a higherconcentration in the presence of calcium chlorid, and utilizing thespent acid in the low concentration treatment. 7

24. The process which comprises separating siomerlc pentylenes andhexylenes by treating them'with hydrochloric acid first at a lowconcentration at ordinary temperatures, separating out the portion actedupon and then treating the unchanged remaining portion with hydrochloricacid at a higher concentration, at ordinary temperatures.

25. The rocess whichcomprises separating isomerlc pentylenes andhexylenes by treating them with hydrochloric acid first" at a lowconcentration at ordinary temperatures, separating out by distillationthe portion acted upon and then treating the unchanged remaining portionwith hydrochloric acid at a higher concentration at ordinarytemperatures. 0

In testimony that I claim the foregoing I have hereunto set my hand.

WALTER E. MASLAND.

Witnesses C. R. MUDGE, A. M. GORMAN.

